The overarching goal of the proposed research is to demonstrate the feasibility of modifying an existing, effective, computer-based, tobacco prevention program, Click City: Tobacco (funded by NIH R01-CA98555), to prevent the initiation of e-cigarette use (e.g., e-cigarettes and other vaping devices) among youth. Click City: Tobacco is a school-based program for 5th graders, with a booster in 6th grade, designed to be delivered prior to smoking initiation. The program?s components each target a specific risk factor predictive of smoking, and each component was evaluated to assure that it changed the targeted factor prior to including it in the final program. In addition, Click City: Tobacco has features that make it appealing to consumers, including a method of delivery that encourages student engagement and fidelity of implementation, and requires little teacher training or implementation time. Results of a randomized trial suggested that the program was effective in decreasing 5th and 6th graders intentions to smoke and their willingness to try smoking if given the opportunity, and that these changes were maintained until the 7th grade (Andrews et al., 2011; Andrews et al., 2014). Within this Phase I SBIR, we propose to accomplish the following aims: (1) Develop two new components which are effective at changing risk factors predictive of future initiation and use of e-cigarettes. Development will consist of a formative process including focus and user testing, and a summative component evaluation using a cross-over design. Within this component evaluation, we will test the hypothesis that each new component changes the risk factor that it was designed to change. (2) Modify two existing components to also target e-cigarette use. Following focus and user testing, we will conduct a component evaluation to test the hypothesis that each revised component changes not only the risk factor associated with e-cigarettes, but also the risk factor associated with cigarettes. Support for our Phase I hypotheses will demonstrate the feasibility of the development process planned for Phase II and the probability that Phase II activities will result in an effective marketable product. Our plans for Phase II include developing additional components targeting e-cigarettes, and modifying all appropriate existing components to also target e-cigarettes use as well as other novel nicotine products. We will also revise the Click City: Tobacco parent newsletters and teacher?s manual. Finally, we will conduct a short-term effectiveness trial in 60 schools across Oregon and Arizona, focusing on schools within counties with a high smoking prevalence. There is a demand for effective, school-based programs for the prevention of e-cigarette and other novel product use. As of August, 2016, there is no evidence indicating that NIH is funding the development and testing of a program designed to prevent the use of e-cigarettes. Thus, the proposed enhanced version of Click City: Tobacco will address an important gap in the marketplace for prevention programs by creating and empirically evaluating a program targeting conventional tobacco products as well as e-cigarettes and other novel nicotine products.